package com.company;

import java.util.Scanner;

public class test {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String test = scanner.nextLine();
        switch (test){
            case "a":
                System.out.println("a");
                break;
            case "b":
                System.out.println("b");
        }
    }
}
